#include "terrain_modifier.h"
#include "core/variant/variant.h"
#include "macros.h"
#include <algorithm>

void TerrainModifier::_bind_methods() {
	BIND_HPROPERTY(Variant::INT, blend_mode, PROPERTY_HINT_ENUM, BlendMode_hint());
	BIND_PROPERTY(Variant::FLOAT, blend_distance);
}

float TerrainModifier::blend(float under, float over, float weight) {
	if (weight <= 0.0) {
		return under;
	}
	over = Math::lerp(under, over, weight);
	float const difference{ under - over };
	float const distance{ Math::abs(difference) };
	// .25 because we need half of each half of the blend range to be used
	float const center_distance{
		this->blend_distance == 0.f
				? 0.f
				: this->blend_distance * 0.25f - distance / this->blend_distance
	};
	if (center_distance < 0.f) {
		if (this->blend_mode == Override) {
			return over;
		} else if (this->blend_mode == Add) {
			return under > over ? under : over;
		} else {
			return under > over ? over : under;
		}
	}
	float const smooth_center_distance{ center_distance * center_distance };
	if (this->blend_mode == Override) {
		return over + smooth_center_distance;
	} else {
		return (this->blend_mode == Add
						? (under > over ? under : over) + smooth_center_distance
						: (under > over ? over : under) - smooth_center_distance);
	}
}

float TerrainModifier::evaluate_at(Vector2 world_coordinate, float before) {
	Vector3 const global_position{ get_global_position() };
	world_coordinate -= { global_position.x, global_position.z };
	return blend(before, 0.0, 1.0);
}

void TerrainModifierDistance::_bind_methods() {
	BIND_HPROPERTY(Variant::OBJECT, distance_weight_curve, PROPERTY_HINT_RESOURCE_TYPE, "Curve");
	BIND_HPROPERTY(Variant::OBJECT, distance_height_curve, PROPERTY_HINT_RESOURCE_TYPE, "Curve");
}

float TerrainModifierDistance::distance_at(Vector2 const &world_coordinate) {
	Vector3 const global_position{ get_global_position() };
	return world_coordinate.distance_to({ global_position.x, global_position.z });
}

float TerrainModifierDistance::evaluate_at(Vector2 world_coordinate, float before) {
	if (this->distance_weight_curve.is_null() || this->distance_height_curve.is_null()) {
		return before;
	}
	float const distance{ distance_at(world_coordinate) };
	float const height_offset{
		std::clamp(distance, this->distance_height_curve->get_min_domain(), this->distance_height_curve->get_max_domain())
	};
	float const weight_offset{
		std::clamp(distance, this->distance_weight_curve->get_min_domain(), this->distance_weight_curve->get_max_domain())
	};
	return blend(before, this->distance_height_curve->sample_baked(height_offset) + get_global_position().y, this->distance_weight_curve->sample_baked(weight_offset));
}

PackedStringArray TerrainModifierDistance::get_configuration_warnings() const {
	PackedStringArray warnings{ super_type::get_configuration_warnings() };
	if (this->distance_weight_curve.is_null()) {
		warnings.push_back("distance_weight_curve is invalid, add a valid distance_weight_curve");
	}
	if (this->distance_height_curve.is_null()) {
		warnings.push_back("distance_height_curve is invalid, add a valid distance_height_curve");
	}
	return warnings;
}